Texarkana has a population of 36,411, according to the last U.S. census. That’s slightly fewer than the crowd that will jam into Fenway Park tonight to watch the old friends face each other when the Boston Red Sox host the St. Louis Cardinals in the World Series opener.

Middlebrooks was a senior at Liberty-Eylau High School in 2007, when Wacha was a sophomore at Pleasant Grove High, about a 10-minute drive away. Now the pair will be in the spotlight as Series rivals.

Wacha, 22, has been a sensation since joining the Cardinals’ rotation in September — Pedro Martinez can’t mention his name on television broadcasts without saying “Wacha! Wacha! Wacha!” like a Pac-Man sound effect. The 25-year-old Middlebrooks has seen extensive action at third base for Boston during the last two seasons.

Bob Bruggeman, a high school umpire for 34 years, remembered umpiring behind the plate for five-to-10 of Wacha’s starts and talked of his dominance. He said citizens of Texarkana are pumped to watch the two on baseball’s biggest stage, and the town might even arrange a parade.

“I’m hoping that right after the Series is over both of them will be able to come back to Texarkana,” he said. “In addition to being a baseball umpire, I’m also the mayor of Texarkana, Texas, so I would like for them if possible to be able to come back to the community to be recognized by the City Council as well as the citizens within the community.”

And the Wacha family will be rooting for both. Wacha and Middlebrooks played on the same American Legion summer team, coached by the pitcher’s father, Tom.

“I don’t think anybody really five years ago would have ever expected it, especially two guys from the same team playing against each other in World Series,” Tom Wacha said.

In a way, the Cardinals have Albert Pujols to thank for Michael Wacha.

St. Louis received the 19th overall pick in the 2012 amateur draft from the Angels as compensation when Pujols left to sign a $240 million, 10-year contract. The Cardinals used the selection of Wacha, who had gone 27-7 during three seasons at Texas A&M — including an 11-strikeout effort against Holy Cross in February 2012.

“He really didn’t start throwing hard until his senior year in high school. He wasn’t like a dominant pitcher,” Middlebrooks said. “He was really good because he knew how to pitch and used all three pitches. Once he got to Texas A&M he got taller and stronger, worked with a lot of good coaches. You look up now and you see 96.”

After rocketing up the minor league system from rookie ball to Triple-A in less than a year, Wacha made his big league debut on May 30 at Kansas City. He didn’t get a decision that night in a rain-interrupted game that ended at 3:14 a.m. but got his first big league victory on June 11 against the Mets. He was sent back to the minors later that month, brought back for 2½ weeks in August, then recalled again after rosters expanded in September.

He was 2-1 with a 1.72 ERA in five September starts, finishing with a near-historic performance against Washington. He was one out from throwing a no-hitter in his ninth big league start when Ryan Zimmerman hit a chopper just over the 6-foot-6 right-hander. Shortstop Pete Kozma charged, grabbed the ball with his bare hand and threw just a little wide, pulling Matt Adams off the bag as Zimmerman arrived.

“I guess it just wasn’t to be,” Wacha said.

And he’s been just as dominant in the postseason, beating Pittsburgh in Game 4 of the division series and Los Angeles in Games 2 and 6 of the league championship series. He’s allowed one run in 21 innings, striking out 22, walking four and holding batters to a .114 average.

“The first impression that he made was he don’t get scared,” Cardinals catcher Yadier Molina said. “When you see a pitcher throwing strikes, 95, 96, with a good changeup and doesn’t get scared, that’s a good sign.”

Wacha is on the right team to learn, with former NL Cy Young Award winner Chris Carpenter and staff ace Adam Wainwright as tutors.

“His maturity level for his age stands out a lot,” Carpenter said, “You get here because you have good stuff and you can pitch. You learn through experience on how to behave, how to act off the field, how to act on the field, how to act in the clubhouse.”

Wacha tried to be calm about the World Series. His parents planned to travel to Boston on Tuesday morning — first, they drove Monday night to watch daughter Brette play volleyball for Pleasant Grove. They planned to make a 3-hour drive after the match to Dallas, where they would catch a morning flight up north.

No matter which team wins, Texarkana will have a champion.

“It’s a huge buzz,” Wacha said. “They’re pretty happy that at least a ring will be coming back there.”